Volumetric dose extension for isodose tuning.

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Imaging

Background:

• Radiotherapy planning requires accurate dose distribution.
• Current methods for dose tuning can be time-consuming.
• Extending dose information from specific surfaces to the whole volume is challenging.

Purpose of the Study:

• To develop a novel method for extending radiation dose from two isosurfaces to the entire patient volume.
• To apply this method for efficient and accurate radiotherapy plan isodose tuning.

Main Methods:

• A three-dimensional lookup table (LUT) was developed, using distances to the 100% and a reference isosurface as variables.
• Voxel doses were binned based on distance and reference dose level, storing mean dose and standard deviation.
• Dose extension was performed by indexing the LUT for each voxel, using a correction strategy for accurate tuning.

Main Results:

• The dose extension method achieved a 92.0% gamma passing rate (5 mm/5%) with a mean error of 4.5% compared to ground truth.
• The method demonstrated high accuracy (97.2% GPR, 3 mm/3%) and efficiency ( < 2 seconds) in simulated interactive isodose tuning.
• The uncertainty estimation from the LUT correlated well with the actual dose differences.

Conclusions:

• A computationally efficient and accurate method for volumetric dose extension from two surfaces was successfully developed.
• This method significantly enhances the process of interactive radiotherapy plan isodose tuning.
• The combination of distance-based LUT and dose correction ensures both speed and precision in treatment planning.